Qihaishu

What is BL24?

BL24, or Qihaishu, is a Bladder-channel point on the low back, about two finger-widths out from the spine at the third lumbar vertebra. Its name translates roughly as "Sea of Qi Transport Point", linking it to Qihai (CV6) on the front of the body.

In classical Chinese medicine, BL24 sits in the long line of Bladder-channel points that run either side of the spine. Tradition uses it for low back ache, stiffness, menstrual complaints and sluggish digestion. It is taught in most acupuncture curricula, usually alongside its neighbours BL23 and BL25.

Two things are worth saying once, up front. Long traditional use is not evidence that a point works, and it is not evidence that pressing it is safe for you. Those are separate questions, and this page keeps them separate.

The honest verdict on evidence: there is no good human research on BL24 on its own. Where the low back has been studied, BL24 usually appears as one point in a larger prescription that was needled by a practitioner, not pressed with a finger. So we cannot say what this single point contributes.

What finger pressure here reliably does is what firm massage of tight paraspinal muscle does anywhere: it can feel good, it can ease a sense of tightness, and the effect is usually short-lived. That is a modest, real thing. It is not treatment for the cause of back pain.

This library is about self-applied finger pressure only. Nothing here involves needles, heat sticks or anything that breaks the skin. If you want needling, that is a trained practitioner's job, not a web page's.

Use BL24 as comfort, not as a verdict on what is wrong with your back. New, severe or changing back pain deserves a proper look from a clinician, especially if anything on the "when to see a doctor" list applies to you.

Where is BL24 and how do you find it?

Find BL24 in the muscle beside the spine, level with the gap below the third lumbar vertebra, roughly two thumb-widths out from the midline.

• Start at your hip bones. Put a hand on each side of your waist and slide down until you hit the top ridge of the pelvis, the iliac crest. Press your thumbs inwards towards your spine at that level.
• Find the L4 level. A line joining the highest points of both hip ridges crosses the spine at about the fourth lumbar vertebra. This is the standard landmark taught for the low back.
• Count up one bump. From that level, move up one spinal knuckle, or roughly 3 cm. You are now at the third lumbar vertebra, and BL24 sits level with the dip just below its tip.
• Move out from the midline. Slide sideways about 1.5 cun, which is two of your own thumb-widths, or about 3 to 4 cm on most adults. Use your own thumb, not an average.
• Feel for muscle, not bone. You should land on the rope of upright muscle running beside the spine. It feels firm and slightly ridged. If you are on hard bone, you have gone too far in.
• Check both sides. BL24 is a paired point, one on each side of the spine. They often feel different, and a more tender side is common rather than meaningful.

Exact vertebra counting is hard on yourself, and even clinicians disagree by a level. What is agreed is the general zone: low back, beside the spine, above the pelvic rim. Working the tender spot in that band is close enough for finger pressure.

If you cannot reach comfortably, lie on your back with a tennis ball under the area, or ask another person to press. Never press anywhere the skin is broken, bruised or rashy.

How do you apply pressure to BL24?

1. Get into position. Stand with hands on your waist, thumbs pointing back, or lie face down on a firm surface. Lying on your back over a small ball also works if reaching is awkward.
2. Place your thumbs. Rest both thumb pads on the muscle band either side of the spine, at the level described above. Keep your wrists relaxed and your shoulders down.
3. Press slowly inwards. Lean your weight in gradually over about five seconds. Aim for a firm ache you would rate 3 or 4 out of 10, never a sharp or shooting feeling.
4. Hold and breathe. Keep steady pressure for 30 to 60 seconds while breathing out slowly. Holding your breath tightens the very muscles you are trying to settle.
5. Add small circles. If a static hold feels dull, make slow circles about a centimetre wide for another 30 seconds. Keep the pressure even rather than jabbing.
6. Release gradually. Ease off over a few seconds rather than lifting off suddenly. Repeat on the other side so both sides get equal attention.
7. Repeat sensibly. Two or three rounds per side, once or twice a day, is plenty. More pressure or more frequency does not buy more benefit.

Stop straight away if you feel any pain running down a leg, numbness, tingling, or a feeling like an electric shock. Those signals belong to nerves, not muscle, and pressing harder makes them worse.

Also stop if the ache keeps climbing after you release, if the skin becomes red and sore, or if you feel lightheaded. A little local tenderness the next day is normal; bruising is not, and means you pressed too hard.

Finger, thumb or a soft ball only. Nothing sharp, nothing that breaks the skin, and no heat applied to numb skin.

What is BL24 traditionally used for?

• Low back ache and stiffness. This is the main traditional use, and it matches where the point sits. Firm pressure on tight low back muscle can ease a sense of tightness for a while, but no trial has tested BL24 pressure on its own. Trials of acupuncture for low back pain that include this region used needles and several points together.
• Lumbar strain after sitting or lifting. Tradition describes BL24 as easing "stagnation" in the lower back. In plain terms, people often find the spot tender after long sitting, and massaging it feels relieving. That is massage doing massage's job, not proof of a point-specific effect.
• Period pain and irregular periods. Classical texts link Qihaishu to the lower abdomen through its namesake, Qihai. Human evidence for acupressure and period pain exists, but the studied points are usually SP6, LI4 and lower abdominal points, not BL24. Treat this claim as untested here.
• Bloating and sluggish digestion. Tradition groups the lower Bladder points with bowel function. There is no controlled human research showing finger pressure at BL24 changes digestion. Any relief is more likely general relaxation.
• Low energy and fatigue. The "Sea of Qi" name invites claims about boosting vitality. There is no human evidence for this at BL24. If fatigue is new, persistent or severe, it needs a medical cause ruled out, not a pressure point.
• Haemorrhoids and pelvic discomfort. Some classical sources list these. No modern human study supports them for this point, and symptoms in that area should be examined rather than self-treated.

Across all of these, the honest summary is the same: the traditional list is long, the human evidence for BL24 specifically is close to empty, and the one plausible real effect is short-term comfort from pressing a tight muscle.

What might regular use of BL24 help prevent?

• Nothing has been shown to be prevented. No human study has tested whether regular finger pressure at BL24 reduces future back pain, period problems or anything else. Any prevention claim you read about this point is tradition or marketing, not research.
• Recurring back stiffness, in theory only. Tradition suggests regular work on the lumbar Bladder points keeps the low back supple. A daily habit of gentle self-massage may help you notice tightness earlier, but that is a reasonable guess rather than a tested outcome.
• What actually has evidence for back pain. Staying active, regular movement, strength work for the hips and trunk, and avoiding long unbroken sitting all have genuine human research behind them for reducing back pain episodes. Treat BL24 as an add-on to those, never a replacement.

If you enjoy the routine, there is no harm in a minute of pressure a day on healthy skin over healthy muscle. Just do not let it delay a proper assessment of back pain that keeps coming back.

Are there tips for using BL24 effectively?

• Warm the area first. A warm shower or a few minutes with a heat pack makes the muscle easier to press and more comfortable. Check the skin is not numb before applying any heat.
• Use your body weight, not your thumbs. Lean into the pressure from your hips rather than squeezing with thumb muscles. This saves your thumb joints and gives steadier, more even pressure.
• Try a ball if you cannot reach. Lie on your back with a tennis ball under the spot and let gravity do the work. Roll off the ball to ease pressure instead of fighting to sit up.
• Breathe out as you press in. A slow exhale lets the back muscles drop. Many people clench and hold their breath without noticing, which cancels out the pressure.
• Stay beside the spine, never on it. The target is the soft muscle band. The bony ridge down the middle is not the point and is uncomfortable to press.
• Keep the sessions short. One or two minutes per side is enough. Long grinding sessions tend to leave the area sore the next day without adding benefit.
• Pair it with movement. Follow pressure with gentle walking, hip hinges or a knee-to-chest stretch. Movement after massage is what tends to make the easing last beyond a few minutes.
• Track what you notice. Jot down the pressure you used and how long the relief lasted. A simple note tells you quickly whether this is worth your time.

If you get nothing from it after a couple of weeks of fair trial, that is a useful result. Spend the time on something with better support for your problem instead.

What do people get wrong with BL24?

• Expecting a cure. This is the biggest one. No acupressure point cures back pain, period problems or fatigue, and anyone promising that is selling something. At best you get temporary comfort.
• Pressing on the spine itself. Landing on the bony midline knuckles instead of the muscle band two thumb-widths out. It hurts, it does nothing useful, and it can bruise thin skin over bone.
• Chasing an exact vertebra. People spend ages counting bumps and give up. The agreed landmark is the hip-crest line at about L4, then one level up; close is good enough for finger pressure.
• Going too hard. Treating pain as proof of effect. Deep digging leaves the back sorer the next day and sometimes bruised, with no extra benefit.
• Pressing through nerve symptoms. Continuing when pain shoots down a leg, or the leg goes numb or tingly. That pattern needs assessment, not more pressure.
• Using it instead of seeing someone. Self-massaging a back that has been getting steadily worse for weeks, instead of getting it checked. Delay is the real harm here.
• Copying needling videos. Some online clips show practitioners needling this area. Nothing in that is transferable to self-care, and you should never attempt anything that pierces skin.
• Ignoring the skin underneath. Pressing over a rash, a mole that has changed, broken skin or a recent surgical scar. Look before you press.

Most mistakes come from treating a traditional point as a mechanism rather than a map reference. Press the tight muscle, keep it gentle, and judge it by how you feel rather than by what the chart promises.

What does the research on BL24 actually say?

There is no useful human research on BL24 by itself. No controlled trial has isolated finger pressure at this point and measured what it does, for back pain or anything else.

What exists is broader. Acupuncture for chronic low back pain has been studied in many randomised trials and several systematic reviews. The general picture is small to moderate short-term improvements, often no better than sham needling, which suggests much of the effect is non-specific. Those studies used needles placed by practitioners, and BL24 was typically one of several lumbar points in a package. You cannot pull one point's contribution out of a package like that.

Acupressure specifically has a much thinner literature. The trials that do exist are usually small, hard to blind properly, and measure outcomes over days rather than months. People know when they are being pressed, which inflates reported benefit. For comparison, PC6 and nausea is the clearest positive case in the whole acupressure field, with repeated controlled trials behind it. BL24 has nothing resembling that.

There is also a plain physiological explanation that does not need channel theory. Firm pressure on tight paraspinal muscle produces local relaxation and a brief drop in reported pain. That is ordinary massage, and it applies to the whole muscle band, not to a one-centimetre spot.

What this means for you: treat BL24 as low-risk comfort with unproven specific effect. If it feels good and the skin and spine underneath are healthy, there is little to lose. If someone cites a study proving BL24 works for a named condition, ask to see it, because as of this page's date that study does not exist in any form we could verify.